| 摘要 |
A bag is formed from a stack of sheets of polyethylene film. The outermost sheet has free edge portions folded inwardly to embrace the free edge portions of the remaining sheets, and the inwardly directed edge portions 20 thermally welded to the adjacent sheet. The stack is then folded so that the inwardly directed portions are adjacent one another and the side edges of the stack are then welded to form a bag. The bag has a greater strength than a corresponding bag made from a single sheet of plastics material having the same overall thickness. The outermost sheet may be of low density, and the remaining sheets of high density, polyethylene. Metallic foam or net-like sheets may be incorporated. <IMAGE> |
